1. Statement of the Invention
This invention relates to the treatment of metal drosses, and more particularly to a new and improved process for separating copper sulfide in the presence or absence of metallic copper from a lead-containing dross wherein relatively low melting temperatures are utilized and a relatively economical and simple-to-operate kettle or similar vessel is employed instead of an expensive, relatively complicated reverberatory furnace.
2. Description of the Prior Art.
U.S. Pat. No. 2,217,981 relates to separating copper from dross containing copper and lead and obtained from the de-copperizing of lead bullion involving charging the dross to a reverberatory furnace, and heating the dross to about 2000.degree. F. to melt the dross. The dross is maintained at about 2000.degree. F. temperature for one hour, after which the fusion products are tapped from the furnace. Metallic lead is thereby liberated and a separate matte phase and dross are formed, the matte phase containing copper sulfide and the dross containing sodium sulfide and a trace of lead. U.S. Pat. No. 1,931,285 relates to treatment of drosses obtained from the melting of lead and lead-bearing alloys, and involving subjecting the dross to prolonged agitation with the molten metal, until the dross releases the metal entrained therewith and becomes dry and of low entrained metal content.
Dross obtained from the copper drossing of lead bullion contains considerable metallic lead entrained in the dross, in addition to copper sulfide. The copper sulfide-containing dross is usually destined for the copper smelter, and it is desirable to separate the copper sulfide of the dross from a major portion, at least, of the metallic lead prior to transferring the copper sulfide-containing dross to to the smelting furnace. The separated metallic lead is sent to the lead refinery for further refining.